Problem: Francine uses $\dfrac23$ cup of pineapple juice for every $\dfrac13$ cup of orange juice to make a smoothie. Enter the number of cups of pineapple juice Francine uses for $1$ cup of orange juice.
Answer: The question is asking how many cups of pineapple juice Francine uses for one cup of orange juice. We can answer this question by finding the unit rate, cups of pineapple juice per cup of orange juice. To find cups of pineapple juice per cup of orange juice, we divide cups of pineapple juice by cups of orange juice. $\phantom{=}\dfrac{~~~ \dfrac23 \text{ cup of pineapple juice}~~~}{\dfrac13 \text{ cup of orange juice}}$ $ = \dfrac{2}3 \div \dfrac13 $ $ = \dfrac{2}{3} \cdot \dfrac31 $ $ =\dfrac{6}{3} $ $ 2$ cups of pineapple juice per cup of orange juice $ $ For $1$ cup of orange juice, Francine uses $2$ cups of pineapple juice.